<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>伪类选择器_动态伪类</title>
    <style>
        a:link {
            color: orange;
        }

        a:visited {
            color: gray;
        }

        a:hover {
            color: skyblue;
        }

        a:active {
            color: green;
        }

        span:hover {
            color: green;
        }

        span:active {
            color: red;
        }

        input:focus,
        select:focus {
            color: orange;
            background-color: green;
        }
    </style>
</head>

<body>
    <a href="https://www.baidu.com">去百度</a>
    <a href="https://www.jd.com">去京东</a>
    <span>尚硅谷</span>
    <br>
    <input type="text">
    <br>
    <input type="text">
    <br>
    <input type="text">
    <select name="" id="">
        <option value="">北京</option>
        <option value="">上海</option>
    </select>
</body>

</html>